In the process of welding a vehicle body in white, it is very important for the application of a grinder. After a period of time of using a welding gun, the surface of an electrode cap can be oxidized or can be glued with impurities, therefore the quality of a welding spot can be affected. The grinder plays a role in grinding the used electrode cap to be in the original appearance, therefore the quality of the welding spot can be ensured. The electrode cap cannot be ground infinitely, therefore a new electrode cap shall be changed after a certain amount of grinding times is reached.
At present, a part for grinding the cap and a part of changing the cap are separated mostly in an automobile production line, and a station is provided with an electrode cap grinder and an electrode cap changer, therefore the electrode cap grinder is used for grinding the electrode cap and the electrode cap changer is used for changing a waste electrode cap; an AIO (All-In-One) machine has not been extensively applied, even the electrode caps are dismounted and changed manually in most factories. The AIO machine has not been extensively applied and the technology has not been manure, one reason is that the difference of the working speeds of the polisher and the cap exchanger is 10 times. When a motor is used, a driving scheme is quiet difficult if large and different driving ratios need to be realized. If a servo motor or a frequency changing motor is used for switching speed, the cost is relatively expensive and an electronic control scheme is complicated. The grinder is extensively and importantly applied in the spot welding process of the whole body in white. If the grinder which is good in performance, convenient to operate, affordable in price and beautiful in appearance is researched, the design of a power source and a driving scheme is a critical part. In addition, the certain influence on beats by the appearance structure of the AIO is a very critical part.
Two driving schemes of an existing grinder are discovered through analysis in the market. One driving scheme is realized by selecting conventional cylindrical gearing, adopting same driving ratio on a polishing end and a cap changing end and realizing the speed difference of the two ends by changing the rotating speed of the motor. The servo motor and the frequency change motor can be used for changing the speeds greatly. Another scheme is that ten times of speed difference of the two ends can be realized by selecting a general single speed asynchronous motor and designing a proper gear driving mechanism.
The implementation principle of the former method is simple, but the requirements on the motor are higher. A compatibility problem exists in a servo system of a servo motor and a control system of a robot, but the frequency change motor needs to be additionally provided with a frequency change control cabinet. In addition, the cost of the AIO machine can be greatly improved by taking the two motors as the power source. However, in the second driving mechanism, the deceleration and speed difference can be realized by adopting the first drive, the processing requirements on the gear are very high, and the processing and manufacturing cost cannot be ignored. In addition to realizing the functions, the grinder needs to be compact in structure and beautiful in appearance, therefore it is difficult to select the second scheme.